A backlight module is a light source arranged behind a panel of a liquid crystal display, the lighting effect of which directly affects the visual effect of a liquid crystal display module.
In a conventional backlight module, for example, in an edge-lighting type backlight module, referring to FIG. 1, when light emitted by a light emitting diode (LED) 101 enter into a light guide plate 102, the light is retro-reflected multiple times within the light guide plate, and a portion of light is changed in wavelength during the procedure, which is converted from visible light into near-infrared light or infrared light, that is, the light is red-shifted. During the visible light converted into near-infrared light, some of the light energy is lost, and the converted near-infrared light is finally converted into heat energy which is dissipated. Since the converted near-infrared light produces some heat energy, the life of an electronic device is affected when the electronic device works under relatively high temperature environment, and since a portion of the light energy is finally converted into heat energy, it reduces the lighting effect of the backlight module and affects the luminance of the light guide plate.
In conclusion, a portion of the light energy of the conventional backlight module is converted into infrared light, and the infrared light is finally converted into heat energy, which affects the life of the electronic device and reduces the lighting effect of the backlight module as well as affects the luminance of the light guide plate.